Boubi begins as a young boy separated from his parents during their scientific expedition in the Southern Ocean. After a shipwreck, he drifts on an iceberg carrying a large pink egg, eventually reaching Pure Island. The egg hatches into the pink dragon Serendipity, forging their bond.

Curious and resilient, Boubi adapts to life on Pure Island with Serendipity and its inhabitants. His relationship with the mermaid princess Laura shifts significantly; initially distrustful of humans due to past tragedies, she gradually accepts Boubi as an ally because of his compassionate nature. Boubi actively defends Pure Island against threats like the treasure-seeking pirate Captain Smudge, who aims to plunder the island's gold and the mermaid's tear.

His protective instincts extend beyond Serendipity to other residents, including the parakeet Pira-Pira, whom he rescues from captivity, and the fruit spirit Akanatsu. Boubi transitions from castaway to dedicated guardian of Pure Island, collaborating with its inhabitants to repel invasions and safeguard their home. He develops leadership qualities, coordinating efforts with allies such as Prime Minister Dolf and the Moai spirits during crises.

Boubi's development emphasizes themes of trust and coexistence as he bridges the divide between humans and Pure Island's magical entities. His commitment to preserving the island's peace remains central to his narrative arc.